How do you move a mercury barometer?

Keep it upright at all times. If you tilt the case flat, air gets into the sealed glass tube and breaks the heavy mercury column. This ruins the vacuum needed for the gauge to function. Always carry them vertically. You might need to plug the cistern tube with a small cork or a specialised transit screw before taking it on a journey.

I have noticed that the weather reading on the brass dial does not match what is actually happening outside today, so is it broken?

The engraved words on the dial are a general guide. Atmospheric pressure changes predict the incoming weather for the next day rather than describing the current rain or sun outside. Tap the glass gently with your knuckle. If the mercury bounces slightly and settles at a new level, the instrument is still reading the local air pressure. The words simply indicate broad trends.

Can I refill the glass tube?

This requires a specialist. Handling mercury carries serious health risks. Restorers use vacuum equipment to boil the liquid metal and remove trapped air.

Why does the small dial at the very top of the wooden case have a different hand and numbers compared to the main section?

That top dial is a hygrometer. It measures moisture in the room rather than the weight of the atmosphere outside. Makers traditionally used a piece of dried oat beard attached to the back of the dial. The plant fibre absorbs moisture from the air, expanding and twisting to physically turn the small brass pointer.

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Georgian Barometers

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Tall wooden wall cases holding a mercury-filled glass tube and an engraved dial, designed to measure atmospheric pressure and forecast the weather in domestic halls.